Method and apparatus for transmitting control information in wireless communication system

ABSTRACT

The present invention relates to a wireless communication system. The present invention relates to a method for transmitting ACK/NACK in a wireless communication system in which carrier aggregation is set, and an apparatus therefor. Specifically, the present invention relates to an ACK/NACK transmission method and an apparatus therefor, the method comprising the steps of: receiving information on a plurality of physical uplink control channel (PUCCH) resources via upper layer signaling; receiving a transmit power control (TPC) field on a secondary carrier through a physical downlink control channel (PDCCH); receiving data indicated by the PDCCH; and transmitting ACK/NACK for the data, wherein the ACK/NACK is transmitted using a PUCCH resource which is indicated by the value of the TPC field among the plurality of PUCCH resources.

TECHNICAL FIELD

The present invention relates to a wireless communication system and,more particularly, to a method and apparatus for transmitting controlinformation. The wireless communication system can support carrieraggregation (CA).

BACKGROUND ART

Extensive research has been conducted to provide various types ofcommunication services including voice and data services in wirelesscommunication systems. In general, a wireless communication system is amultiple access system that supports communication with multiple usersby sharing available system resources (e.g. bandwidth, transmit power,etc.) among the multiple users. The multiple access system may adopt amultiple access scheme such as Code Division Multiple Access (CDMA),Frequency Division Multiple Access (FDMA), Time Division Multiple Access(TDMA), Orthogonal Frequency Division Multiple Access (OFDMA), SingleCarrier Frequency Division Multiple Access (SC-FDMA), etc.

DISCLOSURE Technical Problem

An object of the present invention is to provide a method and apparatusfor efficiently transmitting control information in a wirelesscommunication system. Another object of the present invention is toprovide a channel format, signal processing method and apparatus forefficiently transmitting control information. Another object of thepresent invention is to provide a method and apparatus for efficientlyallocating resources for transmitting control information.

It will be appreciated by persons skilled in the art that the objectsthat could be achieved with the present invention are not limited towhat has been particularly described hereinabove and the above and otherobjects that the present invention could achieve will be more clearlyunderstood from the following detailed description taken in conjunctionwith the accompanying drawings.

Technical Solution

In accordance with one aspect of the present invention, a method for, ata user equipment (UE), transmitting acknowledgement/negative ACK(ACK/NACK) in a wireless communication system in which carrieraggregation is configured includes: receiving information on a pluralityof physical uplink control channel (PUCCH) resources through higherlayer signaling; receiving a transmit power control (TPC) field througha physical downlink control channel (PDCCH) on a secondary carrier;receiving data indicated by the PDCCH; and transmitting ACK/NACK for thedata, wherein the ACK/NACK is transmitted using a PUCCH resource whichis indicated by a value of the TPC field, from among the plurality ofPUCCH resources.

The TPC field may be composed of 2 bits and the value of the TPC fieldmay indicates one of 4 PUCCH resources configured by a higher layer.

The value of the TPC field may be set to the same value in a pluralityof PDCCHs received through a plurality of secondary carriers.

The ACK/NACK may include multiple ACK/NACKs for a plurality of data,wherein the multiple ACK/NACKs are transmitted through a single PUCCHresource.

The PUCCH resource may include at least one of a physical resource blockindex and an orthogonal code index.

The transmitting ACK/NACK may include spreading ACK/NACK informationcorresponding to one single carrier frequency division multiple access(SC-FDMA) symbol such that the spread ACK/NACK information correspondsto a plurality of SC-FDMA symbols; and discrete Fourier transform(DFT)-precoding the spread ACK/NACK information on an SC-FDMA symbolbasis.

In accordance with another embodiment of the present invention, a UEconfigured to transmit ACK/NACK in a wireless communication system inwhich carrier aggregation is configured includes a radio frequency (RF)unit; and a processor, wherein the processor is configured to receiveinformation on a plurality of PUCCH resources through higher layersignaling, to receive a TPC field on a secondary carrier through aPDCCH, to receive data indicated by the PDCCH and to transmit ACK/NACKfor the data, wherein the ACK/NACK is transmitted using a PUCCH resourcewhich is indicated by a value of the TPC field, from among the pluralityof PUCCH resources.

The TPC field may be composed of 2 bits and the value of the TPC fieldmay indicate one of 4 PUCCH resources configured by a higher layer.

The TPC field may be set to the same value in a plurality of PDCCHsreceived through a plurality of secondary carriers.

The ACK/NACK may include multiple ACK/NACKs for a plurality of data,wherein the multiple ACK/NACKs are transmitted through a single PUCCHresource.

The PUCCH resource may include at least one of a physical resource blockindex and an orthogonal code index.

To transmit the ACK/NACK, the processor may be configured to spreadACK/NACK information corresponding to one SC-FDMA symbol such that thespread ACK/NACK information corresponds to a plurality of SC-FDMAsymbols and to discrete Fourier transform (DFT)-precode the spreadACK/NACK information on an SC-FDMA symbol basis.

Advantageous Effects

According to embodiments of the present invention, control informationcan be efficiently transmitted in a wireless communication system.Furthermore, a channel format and a signal processing method forefficiently transmitting control information can be provided. Inaddition, resources for control information transmission can beefficiently allocated.

It will be appreciated by persons skilled in the art that the effectsthat could be achieved with the present invention are not limited towhat has been particularly described hereinabove and these and otheradvantages of the present invention will be more clearly understood fromthe following detailed description taken in conjunction with theaccompanying drawings.

DESCRIPTION OF DRAWINGS

The accompanying drawings, which are included to provide a furtherunderstanding of the invention and are incorporated in and constitute apart of this application, illustrate embodiment(s) of the invention andtogether with the description serve to explain the principle of theinvention.

In the drawings:

FIG. 1 illustrates physical channels used in a 3GPP LTE system, one ofwireless communication systems, and a general signal transmission methodusing the same;

FIG. 2 illustrates an uplink signal processing procedure;

FIG. 3 illustrates a downlink signal processing procedure;

FIG. 4 illustrates SC-FDMA and OFDMA schemes;

FIG. 5 illustrates a signal mapping scheme in a frequency domain, whichsatisfies single carrier property;

FIG. 6 illustrates a signal processing procedure of mapping DFT processoutput samples to a single carrier in clustered SC-FDMA;

FIGS. 7 and 8 illustrate a signal processing procedure of mapping DFTprocess output samples to multiple carriers in clustered SC-FDMA;

FIG. 9 illustrates a signal processing procedure in segmented SC-FDMA;

FIG. 10 illustrates an uplink subframe structure;

FIG. 11 illustrates a signal processing procedure for transmitting areference signal (RS) on uplink;

FIG. 12 illustrates a demodulation reference signal (DMRS) structure fora PUSCH;

FIGS. 13 and 14 illustrate slot level structures of PUCCH formats 1a and1b;

FIGS. 15 and 16 illustrate slot level structures of PUCCH formats2/2a/2b;

FIG. 17 illustrates ACK/NACK channelization for PUCCH formats 1a and 1b;

FIG. 18 illustrates channelization for a hybrid structure of PUCCHformats 1/1a/1b and 2/2a/2b in the same PRB;

FIG. 19 illustrates PRB allocation for PUCCH transmission;

FIG. 20 illustrates a concept of management of downlink componentcarriers in a base station (BS);

FIG. 21 illustrates a concept of management of uplink component carriersin a user equipment (UE);

FIG. 22 illustrates a concept of management of multiple carriers by oneMAC layer in a BS;

FIG. 23 illustrates a concept of management of multiple carriers by oneMAC layer in a UE;

FIG. 24 illustrates a concept of management of multiple carriers bymultiple MAC layers in a BS;

FIG. 25 illustrates a concept of management of multiple carriers bymultiple MAC layers in a UE;

FIG. 26 illustrates a concept of management of multiple carriers bymultiple MAC layers in a BS;

FIG. 27 illustrates a concept of management of multiple carriers by oneor more MAC layers at a receiver of a UE;

FIG. 28 illustrates a general carrier aggregation scenario;

FIG. 29 illustrates a scenario of transmitting uplink controlinformation (UCI) in a carrier aggregation system;

FIG. 30 illustrates signal transmission using PUCCH format 3;

FIG. 31 illustrates PUCCH format 3 and a signal processing procedure forthe same according to an embodiment of the present invention;

FIG. 32 illustrates PUCCH format 3 and a signal processing procedure forthe same according to another embodiment of the present invention;

FIG. 33 illustrates a PUCCH transmission method according to anembodiment of the present invention; and

FIG. 34 illustrates configurations of a BS and a UE applicable to thepresent invention.

BEST MODE

Embodiments of the present invention are applicable to a variety ofwireless access technologies such as Code Division Multiple Access(CDMA), Frequency Division Multiple Access (FDMA), Time DivisionMultiple Access (TDMA), Orthogonal Frequency Division Multiple Access(OFDMA), Single Carrier Frequency Division Multiple Access (SC-FDMA),etc. CDMA can be implemented as a wireless technology such as UniversalTerrestrial Radio Access (UTRA) or CDMA2000. TDMA can be implemented asa wireless technology such as Global System for Mobile communications(GSM)/General Packet Radio Service (GPRS)/Enhanced Data Rates for GSMEvolution (EDGE). OFDMA can be implemented as a wireless technology suchas Institute of Electrical and Electronics Engineers (IEEE) 802.11(Wireless Fidelity (Wi-Fi)), IEEE 802.16 (Worldwide interoperability forMicrowave Access (WiMAX)), IEEE 802.20, Evolved UTRA (E-UTRA). UTRA is apart of Universal Mobile Telecommunications System (UMTS). 3^(rd)Generation Partnership Project (3GPP) Long Term Evolution (LTE) is apart of Evolved UMTS (E-UMTS) using E-UTRA. LTE-Advanced (LTE-A) is anevolution of 3GPP LTE. While the following description is given,centering on 3GPP LTE/LTE-A for clarity of description, this is purelyexemplary and thus should not be construed as limiting the presentinvention.

In a wireless communication system, a UE receives information from a BSthrough downlink and transmits information to the BS through uplink.Information transmitted and received between the BS and the UE includesdata and various types of control information. Various physical channelsare present according to type/usage of information transmitted andreceived between the BS and the UE.

FIG. 1 illustrates physical channels used in a 3GPP LTE system and asignal transmission method using the same.

When powered on or when a UE initially enters a cell, the UE performsinitial cell search involving synchronization with a BS in step S101.For initial cell search, the UE may be synchronized with the BS andacquire information such as a cell Identifier (ID) by receiving aPrimary Synchronization Channel (P-SCH) and a Secondary SynchronizationChannel (S-SCH) from the BS. Then the UE may receive broadcastinformation from the cell on a physical broadcast channel. In the meantime, the UE may check a downlink channel status by receiving a DownlinkReference Signal (DL RS) during initial cell search.

After initial cell search, the UE may acquire more specific systeminformation by receiving a Physical Downlink Control Channel (PDCCH) andreceiving a Physical Downlink Shared Channel (PDSCH) based oninformation of the PDCCH in step S102.

The UE may perform a random access procedure to access the BS in stepsS103 to S106. For random access, the UE may transmit a preamble to theBS on a Physical Random Access Channel (PRACH) (S103) and receive aresponse message for the preamble on a PDCCH and a PDSCH correspondingto the PDCCH (S104). In the case of contention-based random access, theUE may perform a contention resolution procedure by further transmittingthe PRACH (S105) and receiving a PDCCH and a PDSCH corresponding to thePDCCH (S106).

After the foregoing procedure, the UE may receive a PDCCH/PDSCH (S107)and transmit a Physical Uplink Shared Channel (PUSCH)/Physical UplinkControl Channel (PUCCH) (S108), as a general downlink/uplink signaltransmission procedure. Here, control information transmitted from theUE to the BS is called uplink control information (UCI). The UCI mayinclude a Hybrid Automatic Repeat and requestAcknowledgement/Negative-ACK (HARQ ACK/NACK) signal, scheduling request(SR), a Channel Quality Indicator (CQI), a Precoding Matrix Index (PMI),a Rank Indication (RI), etc. While the UCI is transmitted through aPUCCH in general, it may be transmitted through a PUSCH when controlinformation and traffic data need to be simultaneously transmitted. TheUCI may be aperiodically transmitted through a PUSCH at therequest/instruction of a network.

FIG. 2 illustrates a signal processing procedure through which a UEtransmits an uplink signal.

To transmit the uplink signal, a scrambling module 210 of the UE mayscramble the uplink signal using a UE-specific scramble signal. Thescrambled signal is input to a modulation mapper 220 in which thescrambled signal is modulated into complex symbols using Binary PhaseShift Keying (BPSK), Quadrature Phase Shift Keying (QPSK) or16-Quadrature amplitude Modulation (QAM)/64-QAM according to signal typeand/or channel status. The modulated complex symbols are processed by atransform precoder 230, and then applied to a resource element mapper240. The resource element mapper 240 may map the complex symbols totime-frequency resource elements. The signal processed in this mannermay be subjected to an SC-FDMA signal generator 250 and transmitted to aBS through an antenna.

FIG. 3 illustrates a signal processing procedure through which the BStransmits a downlink signal.

In a 3GPP LTE system, the BS may transmit one or more codewords ondownlink. The codewords may be processed into complex symbols through ascrambling module 301 and a modulation mapper 302 as in the uplink shownin FIG. 2. Then, the complex symbols are mapped to a plurality of layersby a layer mapper 303. The layers may be multiplied by a precodingmatrix in a precoding module 304 and allocated to transport antennas.The processed signals for the respective antennas may be mapped totime-frequency resource elements by a resource element mapper 305 andsubjected to an OFDM signal generator 306 to be transmitted through theantennas.

When the UE transmits an uplink signal in a wireless communicationsystem, a peak-to-average ratio (PAPR) becomes a problem, as compared toa case in which the BS transmits a downlink signal. Accordingly, uplinksignal transmission uses SC-FDMA while downlink signal transmission usesOFDMA, as described above with reference to FIGS. 2 and 3.

FIG. 4 illustrates SC-FDMA and OFDMA schemes. The 3GPP system employsOFDMA in downlink and uses SC-FDMA in uplink.

Referring to FIG. 4, both a UE for transmitting an uplink signal and aBS for transmitting a downlink signal include a serial-to-parallelconverter 401, a subcarrier mapper 403, an M-point IDFT module 404, anda cyclic prefix (CP) adder 406. The UE for transmitting a signalaccording to SC-FDMA additionally includes an N-point DFT module 402.The N-point DFT module 402 offsets some of the IDFT effect of theM-point IDFT module 404 such that a transmitted signal has singlecarrier property.

FIG. 5 illustrates a signal mapping scheme in a frequency domain, whichsatisfies single carrier property. FIG. 5( a) illustrates a localizedmapping scheme and FIG. 5B illustrates a distributed mapping scheme.

Clustered SC-FDMA, which is a modified version of SC-FDMA, will now bedescribed. Clustered SC-FDMA divides DFT process output samples intosub-groups in a subcarrier mapping process and discretely maps thesub-groups to the frequency domain (or subcarrier domain).

FIG. 6 illustrates a signal processing procedure for mapping DFT processoutput samples to a single carrier in clustered SC-FDMA. FIGS. 7 and 8illustrate a signal processing procedure for mapping DFT process outputsamples to multiple carriers in clustered SC-FDMA. FIG. 6 shows anexample of application of intra-carrier clustered SC-FDMA while FIGS. 7and 8 show examples of application of inter-carrier clustered SC-FDMA.FIG. 7 illustrates a case in which a signal is generated through asingle IFFT block when subcarrier spacing between neighboring componentcarriers is set while component carriers are contiguously allocated inthe frequency domain. FIG. 8 shows a case in which a signal is generatedthrough a plurality of IFFT blocks when component carriers arenon-contiguously allocated in the frequency domain.

FIG. 9 illustrates a signal processing procedure in segmented SC-FDMA.

Segmented SC-FDMA is a simple extension of the DFT spreading and IFFTsubcarrier mapping structure of the conventional SC-FDMA, when thenumber of DFT blocks is equal to the number of IFFT blocks and thus theDFT blocks and the IFFT blocks are in one-to-one correspondence. Whilethe term ‘segmented SC-FDMA’ is adopted herein, it may also be calledN×SC-FDMA or N×DFT spread OFDMA (N×DFT-s-OFDMA). Referring to FIG. 9,the segmented SC-FDMA is characterized in that total time-domainmodulation symbols are divided into N groups (N is an integer largerthan 1) and a DFT process is performed on a group-by-group basis torelieve the single carrier property constraint.

FIG. 10 illustrates an uplink subframe structure.

Referring to FIG. 10, an uplink subframe includes a plurality of slots(e.g. two slots). The slots may include different numbers of SC-FDMAsymbols according to CP length. For example, the slot can include 7SC-FDMA symbols in case of normal CP. The uplink subframe is dividedinto a data region and a control region. The data region includes aPUSCH and is used to transmit a data signal such as voice. The controlregion includes a PUCCH and is used to transmit uplink controlinformation. The PUCCH includes RB pairs (e.g. 7 RB pairs in frequencymirrored positions, and m=0, 1, 2, 3, 4) located on both ends of thedata region in the frequency domain and is hopped on a slot basis. Theuplink control information (UCI) includes HARQ ACK/NACK, CQI, PMI, RI,etc.

FIG. 11 illustrates a signal processing procedure for transmitting areference signal (RS) on uplink. While data is converted into afrequency domain signal through a DFT precoder, frequency-mapped, andthen transmitted through IFFT, an RS does not passes the DFT precoder.Specifically, an RS sequence generated in the frequency domain (S11) issequentially subjected to localization mapping (S12), IFFT (S13) and CPaddition (S14) to be transmitted.

RS sequence r_(u,v) ^((α))(n) is defined by cyclic shift α of a basesequence and may be represented by Equation 1.

r _(u,v) ^((α))(n)=e ^(jαn) r _(u,v)(n), 0≦n<M _(sc) ^(RS)  [Equation 1]

Here, M_(sc) ^(RS)=mN_(sc) ^(RB) denotes the length of the RS sequence,N_(sc) ^(RB) denotes a resource block size on a subcarrier basis,1≦m≦N_(RB) ^(max,UL), and N_(RB) ^(max,UL) represents a maximum uplinktransmission bandwidth.

Base sequence r _(u,v)(n) is divided into several groups. uε{0, 1, . . ., 29} denotes a group number and v corresponds to a base sequence numberin a corresponding group. Each group includes one base sequence (v=0)having a length of M_(sc) ^(RS)=mN_(sc) ^(RB) (1≦m≦5) and two basesequences (v=0,1) having a length of M_(sc) ^(RS)=mN_(sc) ^(RB)(6≦m≦N_(RB)^(max,UL). The sequence group number u and base sequence number v in the corresponding group may vary with time. Base sequence r)_(u,v)(0), . . . , r _(u,v) (M_(sc) ^(RS)−1) is defined according tosequence length M_(sc) ^(RS).

A base sequence having a length of longer than 3N_(sc) ^(RB) can bedefined as follows.

For M_(sc) ^(RS)≧3N_(sc) ^(RB), base sequence r _(u,v)(0), . . . , r_(u,v)(M_(sc) ^(RS)−1) is given by the following Equation 2.

r _(u,v)(n)=x _(q)(n mod N _(ZC) ^(RS)), 0≦n<M _(sc) ^(RS)  [Equation 2]

Here, the q-th root Zadoff-Chu sequence can be defined by the followingEquation 3.

$\begin{matrix}{{{x_{q}(m)} = ^{{- j}\frac{\pi \; {{qm}{({m + 1})}}}{N_{ZC}^{RS}}}},{0 \leq m \leq {N_{ZC}^{RS} - 1}}} & \left\lbrack {{Equation}\mspace{14mu} 3} \right\rbrack\end{matrix}$

Here, q satisifes the following Equation 4.

q=└( q+1/2┘+v·(−1)^(└2 q┘)

q=N _(ZC) ^(RS)·(u+1)/31  [Equation 4]

The length N_(ZC) ^(RS) of the Zadoff-Chue sequence is given by thelargest prime number, and thus N_(ZC) ^(RS)<M_(sc) ^(RS) is satisfied.

A base sequence having a length of less than 3N_(sc) ^(RB) can bedefined as follows. The base sequence is given by the following Equation5 for M_(sc) ^(RS)=N_(sc) ^(RB) and M_(sc) ^(RS)=2N_(sc) ^(RB).

r _(u,v)(n)=e ^(jφ(n)π/4), 0≦n≦M _(sc) ^(RS)  [Equation 5]

Here, for M_(sc) ^(RS)=N_(sc) ^(RB) and M_(sc) ^(RS)=2N_(sc) ^(RB), φ(n)is given as shown in Tables 1 and 2, respectively.

TABLE 1 u φ(0), . . . , φ(11) 0 −1 1 3 −3 3 3 1 1 3 1 −3 3 1 1 1 3 3 3−1 1 −3 −3 1 −3 3 2 1 1 −3 −3 −3 −1 −3 −3 1 −3 1 −1 3 −1 1 1 1 1 −1 −3−3 1 −3 3 −1 4 −1 3 1 −1 1 −1 −3 −1 1 −1 1 3 5 1 −3 3 −1 −1 1 1 −1 −1 3−3 1 6 −1 3 −3 −3 −3 3 1 −1 3 3 −3 1 7 −3 −1 −1 −1 1 −3 3 −1 1 −3 3 1 81 −3 3 1 −1 −1 −1 1 1 3 −1 1 9 1 −3 −1 3 3 −1 −3 1 1 1 1 1 10 −1 3 −1 11 −3 −3 −1 −3 −3 3 −1 11 3 1 −1 −1 3 3 −3 1 3 1 3 3 12 1 −3 1 1 −3 1 1 1−3 −3 −3 1 13 3 3 −3 3 −3 1 1 3 −1 −3 3 3 14 −3 1 −1 −3 −1 3 1 3 3 3 −11 15 3 −1 1 −3 −1 −1 1 1 3 1 −1 −3 16 1 3 1 −1 1 3 3 3 −1 −1 3 −1 17 −31 1 3 −3 3 −3 −3 3 1 3 −1 18 −3 3 1 1 −3 1 −3 −3 −1 −1 1 −3 19 −1 3 1 31 −1 −1 3 −3 −1 −3 −1 20 −1 −3 1 1 1 1 3 1 −1 1 −3 −1 21 −1 3 −1 1 −3 −3−3 −3 −3 1 −1 −3 22 1 1 −3 −3 −3 −3 −1 3 −3 1 −3 3 23 1 1 −1 −3 −1 −3 1−1 1 3 −1 1 24 1 1 3 1 3 3 −1 1 −1 −3 −3 1 25 1 −3 3 3 1 3 3 1 −3 −1 −13 26 1 3 −3 −3 3 −3 1 −1 −1 3 −1 −3 27 −3 −1 −3 −1 −3 3 1 −1 1 3 −3 −328 −1 3 −3 3 −1 3 3 −3 3 3 −1 −1 29 3 −3 −3 −1 −1 −3 −1 3 −3 3 1 −1

TABLE 2 u φ(0), . . . , φ(23) 0 −1 3 1 −3 3 −1 1 3 −3 3 1 3 −3 3 1 1 −11 3 −3 3 −3 −1 −3 1 −3 3 −3 −3 −3 1 −3 −3 3 −1 1 1 1 3 1 −1 3 −3 −3 1 31 1 −3 2 3 −1 3 3 1 1 −3 3 3 3 3 1 −1 3 −1 1 1 −1 −3 −1 −1 1 3 3 3 −1 −31 1 3 −3 1 1 −3 −1 −1 1 3 1 3 1 −1 3 1 1 −3 −1 −3 −1 4 −1 −1 −1 −3 −3 −11 1 3 3 −1 3 −1 1 −1 −3 1 −1 −3 −3 1 −3 −1 −1 5 −3 1 1 3 −1 1 3 1 −3 1−3 1 1 −1 −1 3 −1 −3 3 −3 −3 −3 1 1 6 1 1 −1 −1 3 −3 −3 3 −3 1 −1 −1 1−1 1 1 −1 −3 −1 1 −1 3 −1 −3 7 −3 3 3 −1 −1 −3 −1 3 1 3 1 3 1 1 −1 3 1−1 1 3 −3 −1 −1 1 8 −3 1 3 −3 1 −1 −3 3 −3 3 −1 −1 −1 −1 1 −3 −3 −3 1 −3−3 −3 1 −3 9 1 1 −3 3 3 −1 −3 −1 3 −3 3 3 3 −1 1 1 −3 1 −1 1 1 −3 1 1 10−1 1 −3 −3 3 −1 3 −1 −1 −3 −3 −3 −1 −3 −3 1 −1 1 3 3 −1 1 −1 3 11 1 3 3−3 −3 1 3 1 −1 −3 −3 −3 3 3 −3 3 3 −1 −3 3 −1 1 −3 1 12 1 3 3 1 1 1 −1−1 1 −3 3 −1 1 1 −3 3 3 −1 −3 3 −3 −1 −3 −1 13 3 −1 −1 −1 −1 −3 −1 3 3 1−1 1 3 3 3 −1 1 1 −3 1 3 −1 −3 3 14 −3 −3 3 1 3 1 −3 3 1 3 1 1 3 3 −1 −1−3 1 −3 −1 3 1 1 3 15 −1 −1 1 −3 1 3 −3 1 −1 −3 −1 3 1 3 1 −1 −3 −3 −1−1 −3 −3 −3 −1 16 −1 −3 3 −1 −1 −1 −1 1 1 −3 3 1 3 3 1 −1 1 −3 1 −3 1 1−3 −1 17 1 3 −1 3 3 −1 −3 1 −1 −3 3 3 3 −1 1 1 3 −1 −3 −1 3 −1 −1 −1 181 1 1 1 1 −1 3 −1 −3 1 1 3 −3 1 −3 −1 1 1 −3 −3 3 1 1 −3 19 1 3 3 1 −1−3 3 −1 3 3 3 −3 1 −1 1 −1 −3 −1 1 3 −1 3 −3 −3 20 −1 −3 3 −3 −3 −3 −1−1 −3 −1 −3 3 1 3 −3 −1 3 −1 1 −1 3 −3 1 −1 21 −3 −3 1 1 −1 1 −1 1 −1 31 −3 −1 1 −1 1 −1 −1 3 3 −3 −1 1 −3 22 −3 −1 −3 3 1 −1 −3 −1 −3 −3 3 −33 −3 −1 1 3 1 −3 1 3 3 −1 −3 23 −1 −1 −1 −1 3 3 3 1 3 3 −3 1 3 −1 3 −1 33 −3 3 1 −1 3 3 24 1 −1 3 3 −1 −3 3 −3 −1 −1 3 −1 3 −1 −1 1 1 1 1 −1 −1−3 −1 3 25 1 −1 1 −1 3 −1 3 1 1 −1 −1 −3 1 1 −3 1 3 −3 1 1 −3 −3 −1 −126 −3 −1 1 3 1 1 −3 −1 −1 −3 3 −3 3 1 −3 3 −3 1 −1 1 −3 1 1 1 27 −1 −3 33 1 1 3 −1 −3 −1 −1 −1 3 1 −3 −3 −1 3 −3 −1 −3 −1 −3 −1 28 −1 −3 −1 −1 1−3 −1 −1 1 −1 −3 1 1 −3 1 −3 −3 3 1 1 −1 3 −1 −1 29 1 1 −1 −1 −3 −1 3 −13 −1 1 3 1 −1 3 1 3 −3 −3 1 −1 −1 1 3 RS hopping will now be described.

The sequence group number u in slot n_(s) can be defined by grouphopping pattern f_(gh)(n_(s)) and a sequence-shift pattern f_(ss)according to Equation 6.

u=(f _(gh)(n _(s))+f _(ss))mod30  [Equation 6]

Here, mod denotes a modulo operation.

There are 17 different hopping patterns and 30 different sequence-shiftpatterns. Sequence group hopping may be enabled or disabled by means ofa parameter that enables group hopping and is provided by higher layers.

PUCCH and PUSCH have the same hopping pattern but may have differentsequence-shift patterns.

The group hopping pattern f_(gh)(n_(s)) is the same for PUSCH and PUCCHand given by the following Equation 7.

$\begin{matrix}{{f_{gh}\left( n_{s} \right)} = \left\{ \begin{matrix}0 & {{if}\mspace{14mu} {group}\mspace{14mu} {hopping}\mspace{14mu} {is}\mspace{14mu} {disabled}} \\{\left( {\sum\limits_{i = 0}^{7}{{c\left( {{8\; n_{s}} + i} \right)} \cdot 2^{i}}} \right){mod}\; 30} & {{if}\mspace{14mu} {group}\mspace{14mu} {hopping}\mspace{14mu} {is}\mspace{14mu} {enabled}}\end{matrix} \right.} & \left\{ {{Equation}\mspace{14mu} 7} \right\rbrack\end{matrix}$

Here, c(i) corresponds to a pseudo-random sequence and the pseudo-randomsequence generator may be initialized with

$c_{init} = \left\lfloor \frac{N_{ID}^{cell}}{30} \right\rfloor$

at the beginning of each radio frame.

Sequence-shift pattern f_(ss) differs between PUCCH and PUSCH.

For PUCCH, sequence-shift pattern f_(ss) ^(PUCCH) is given by f_(ss)^(PUCCH)=N_(ID) ^(cell) mod30. For PUSCH, sequence shift pattern f_(ss)^(PUCCH) is given by f_(ss) ^(PUCCH)=(f_(ss) ^(PUCCH)+Δ_(ss))mod30.Δ_(ss)ε{0, 1, . . . , 29} is configured by higher layers.

Sequence hopping will now be described.

Sequence hopping only applies for reference signals of length M_(sc)^(RS)≧6N_(sc) ^(RB).

For reference signals of length M_(sc) ^(RS)<6N_(sc) ^(RB), the basesequence number v within the base sequence group is given by v=0.

For reference signals of length M_(sc) ^(RS)≧6N_(sc) ^(RB), the basesequence number v within the base sequence group in slot n_(s) is givenby the following Equation 8.

$\begin{matrix}{v = \left\{ \begin{matrix}{{{c\left( n_{s} \right)}\mspace{14mu} {if}\mspace{14mu} {group}\mspace{14mu} {hopping}\mspace{14mu} {is}\mspace{14mu} {disabled}}\mspace{11mu}} \\{\; {{and}\mspace{14mu} {sequence}\mspace{14mu} {hopping}\mspace{14mu} {is}\mspace{14mu} {enabled}}} \\{0\mspace{14mu} {otherwise}}\end{matrix} \right.} & \left\lbrack {{Equation}\mspace{14mu} 8} \right\rbrack\end{matrix}$

Here, c(i) corresponds to the pseudo-random sequence and a parameterthat is provided by higher layers and enables sequence hoppingdetermines if sequence hopping is enabled or not. The pseudo-randomsequence generator may be initialized with

$c_{init} = {{\left\lfloor \frac{N_{ID}^{cell}}{30} \right\rfloor \cdot 2^{5}} + f_{ss}^{PUSCH}}$

at the beginning of each radio frame.

A reference signal for PUSCH is determined as follows.

Reference signal sequence r^(PUSCH)(.) for PUSCH is defined byr^(PUSCH)(m·M_(sc) ^(RS)+n)=r_(u,v) ^((α))(n) where

m = 0, 1 n = 0, …  , M_(sc)^(RS) − 1

and M_(sc) ^(RS)=M_(sc) ^(PUSCH).

A cyclic shift is given by α=2n_(cs)/12 and n_(cs)=(n_(DMRS)⁽¹⁾+n_(DMRS) ⁽²⁾+n_(PRD)(n_(s)))mod12 in one slot.

Here, n_(DMRS) ⁽¹⁾ is a broadcast value, n_(DMRS) ⁽²⁾ is given by uplinkscheduling allocation, and n_(PRS)(n_(s)) is a cell-specific cyclicshift value. n_(PRS)(n_(s)) varies with slot number n_(s) and is givenby n_(PRS)(n_(s))=Σ_(i=0) ⁷c(8·n_(s)+i)·2^(i).

Here, c(i) denotes the psedo-random sequence and is a cell-specificvalue. The psedo-random sequence generator may be initialized with

$c_{init} = {{\left\lfloor \frac{N_{ID}^{cell}}{30} \right\rfloor \cdot 2^{5}} + f_{ss}^{PUSCH}}$

at the beginning of each radio frame.

Table 3 shows a cyclic shift field and n_(DMRS) ⁽²⁾ in downlink controlinformation (DCI) format 0.

TABLE 3 Cyclic shift field in DCI format 0 n_(DMRS) ⁽²⁾ 000 0 001 2 0103 011 4 100 6 101 8 110 9 111 10

A physical mapping method for an uplink RS in a PUSCH will now bedescribed.

The sequence is multiplied with the amplitude scaling factor β_(PUSCH)and mapped to the same set of a physical resource block (PRB) used forthe corresponding PUSCH in a PUSCH sequence starting with r^(PUSCH)(0).Mapping to resource elements (k,l), with l=3 for normal CP and l=2 forextended CP, in the subframe will be in increasing order of first k,then the slot number.

In summary, a ZC sequence is used with cyclic extension for length3N_(sc) ^(RB) or larger, whereas a computer generated sequence is usedfor length less than 3N_(sc) ^(RB). A cyclic shift is determinedaccording to cell-specific cyclic shift, UE-specific cyclic shift andhopping pattern.

FIG. 12 a shows a DMRS structure for PUSCH in case of normal CP and FIG.12 b shows a DMRS structure for PUSCH in case of extended CP. A DMRS istransmitted through the fourth and eleventh SC-FDMA symbols in FIG. 12 aand transmitted through the third and ninth SC-FDMA symbols in FIG. 12b.

FIGS. 13 to 16 illustrate slot level structures of PUCCH formats. APUCCH has the following formats in order to transmit controlinformation.

(1) Format 1: on-off keying (OOK) modulation, used for schedulingrequest (SR).

(2) Formats 1a and 1b: used for ACK/NACK transmission.

-   -   1) Format 1a: BPSK ACK/NACK for one codeword    -   2) Format 1b: QPSK ACK/NACK for two codewords

(3) Format 2: QPSK modulation, used for CQI transmission.

(4) Formats 2a and 2b: used for simultaneous transmission of CQI andACK/NACK

Table 4 shows modulation schemes according to PUCCH format and thenumber of bits per subframe. Table 5 shows the number of RSs per slotaccording to PUCCH format and Table 6 shows SC-FDMA symbol position inan RS according to PUCCH format. In Table 4, PUCCH formats 2a and 2bcorrespond to normal CP.

TABLE 4 PUCCH Number of bits per format Modulation scheme subframe(M_(bit)) 1 N/A N/A 1a BPSK 1 1b QPSK 2 2 QPSK 20 2a QPSK + BPSK 21 2bQPSK + BPSK 22

TABLE 5 PUCCH format Normal CP Extended CP 1, 1a, 1b 3 2 2 2 1 2a, 2b 2N/A

TABLE 6 PUCCH SC-FDMA symbol position in RS format Normal CP Extended CP1, 1a, 1b 2, 3, 4 2, 3 2, 2a, 2b 1, 5 3

FIG. 13 illustrates PUCCH formats 1a and 1b in case of normal CP andFIG. 14 illustrates PUCCH formats 1a and 1b in case of extended CP. InPUCCH formats 1a and 1b, the same control information is repeated in asubframe on a slot-by-slot basis. ACK/NACK signals are respectivelytransmitted from UEs through different resources composed of differentcyclic shifts (CSs) (frequency domain codes) and orthogonal cover codes(OCs or OCCs) (time domain spreading codes) of a computer-generatedconstant amplitude zero auto correlation (CG-CAZAC) sequence. An OCincludes a Walsh/DFT orthogonal code, for example. If the number of CSsis 6 and the number of OCs is 3, a total of 18 UEs can be multiplexed inthe same physical resource block (PRB) on a single antenna basis.Orthogonal sequence w0,w1,w2,w3 may be applied in an arbitrary timedomain (after FFT) or in an arbitrary frequency domain (prior to FFT).

An ACK/NACK resource composed of a CS, OC and PRB may be given to a UEthrough radio resource control (RRC) for SR and persistent scheduling.The ACK/NACK resource may be implicitly provided to the UE by a lowestCCE index of a PUCCH corresponding to a PDSCH for dynamic ACK/NACK andnon-persistent scheduling.

FIG. 15 illustrates PUCCH formats 2/2a/2b in case of normal CP and FIG.16 illustrates PUCCH formats 2/2a/2b in case of extended CP. Referringto FIGS. 15 and 16, one subframe includes 10 QPSK data symbols inaddition to RS symbols in case of normal CP. Each of the QPSK symbols isspread in the frequency domain according to CS and then mapped to acorresponding SC-FDMA symbol. SC-FDMA symbol level CS hopping may beapplied to randomize inter-cell interference. An RS may be multiplexedaccording to CDM using CSs. For example, if the number of available CSsis 12 or 6, 12 or 6 UEs can be multiplexed in the same PRB. That is, aplurality of UEs can be multiplexed according to CS+OC+PRB and CS+PRB inPUCCH formats 1/1a/1b and 2/2a/2b.

Orthogonal sequences with length-4 and length-3 for PUCCH formats1/1a/1b are shown in Table 7 and Table 8.

TABLE 7 Length-4 orthogonal sequences for PUCCH formats 1/1a/1b Sequenceindex Orthogonal sequences n_(oc)(n_(s)) [w(0) . . . w(N_(SF) ^(PUCCH) −1] 0 [+1 +1 +1 +1] 1 [+1 −1 +1 −1] 2 [+1 −1 −1 +1]

TABLE 8 Length-3 orthogonal sequences for PUCCH formats 1/1a/1b Sequenceindex Orthogonal sequences n_(oc)(n_(s)) [w(0) . . . w(N_(SF) ^(PUCCH) −1)] 0 [1 1 1] 1 [1 e^(j2π/3) e^(j4π/3)] 2 [1 e^(j4π/3) e^(j2π/3)]

Orthogonal sequences for an RS in PUCCH formats 1/1a/1b are shown inTable 9.

TABLE 9 1a and 1b Sequence index n _(oc) (n_(s)) Normal cyclic prefixExtended cyclic prefix 0 [1 1 1] [1 1] 1 [1 e^(j2π/3) e^(j4π/3)] [1 −1]2 [1 e^(j4π/3) e^(j2π/3)] N/A

FIG. 17 illustrates ACK/NACK channelization for PUCCH formats 1a and 1b.FIG. 17 corresponds to a case of Δ_(shift) ^(PUCCH)−2.

FIG. 18 illustrates channelization for a hybrid structure of PUCCHformats 1/1a/1b and 2/2a/2b in the same PRB.

CS hopping and OC remapping may be applied as follows.

(1) Symbol-based cell-specific CS hopping for randomization ofinter-cell interference

(2) Slot level CS/OC remapping

-   -   1) For inter-cell interference randomization    -   2) Slot-based access for mapping between ACK/NACK channels and        resources (k)

Resource n_(r) for PUCCH formats 1/1a/1b includes the followingcombination.

(1) CS (corresponding to a DFT orthogonal code at a symbol level) n_(cs)

(2) OC (orthogonal code at a slot level) n_(oc)

(3) Frequency resource block (RB) n_(rb)

When indexes indicating CS, OC and RB are n_(cs), n_(oc), and n_(rb),respectively, a representative index n_(r) includes n_(cs), n_(oc) andn_(rb). Here, n_(r) satisfies n_(r)=(n_(cs), n_(oc), n_(rb)).

CQI, PMI, RI and a combination of CQI and ACK/NACK may be transmittedthrough PUCCH formats 2/2a/2b. In this case, Reed-Muller (RM) channelcoding is applicable.

For example, channel coding for a UL CQI in an LTE system is describedas follows. Bit sequence is α₀, α₁, α₂, α₃, . . . , α_(A-1)channel-coded using RM code (20,A). Table 10 shows a base sequence forcode (20,A). Here, α₀ and α_(A-1) denote a most significant bit (MSB)and a least significant bit (LSB). In the case of extended CP, a maximumnumber of information bits is 11 in cases other than a case in which CQIand ACK/NACK are simultaneously transmitted. The UI CQI may be subjectedto QPSK modulation after being coded into 20 bits using the RM code. Thecoded bits may be scrambled before being subjected to QPSK modulation.

TABLE 10 I M_(i,0) M_(i,1) M_(i,2) M_(i,3) M_(i,4) M_(i,5) M_(i,6)M_(i,7) M_(i,8) M_(i,9) M_(i,10) M_(i,11) M_(i,12) 0 1 1 0 0 0 0 0 0 0 01 1 0 1 1 1 1 0 0 0 0 0 0 1 1 1 0 2 1 0 0 1 0 0 1 0 1 1 1 1 1 3 1 0 1 10 0 0 0 1 0 1 1 1 4 1 1 1 1 0 0 0 1 0 0 1 1 1 5 1 1 0 0 1 0 1 1 1 0 1 11 6 1 0 1 0 1 0 1 0 1 1 1 1 1 7 1 0 0 1 1 0 0 1 1 0 1 1 1 8 1 1 0 1 1 00 1 0 1 1 1 1 9 1 0 1 1 1 0 1 0 0 1 1 1 1 10 1 0 1 0 0 1 1 1 0 1 1 1 111 1 1 1 0 0 1 1 0 1 0 1 1 1 12 1 0 0 1 0 1 0 1 1 1 1 1 1 13 1 1 0 1 0 10 1 0 1 1 1 1 14 1 0 0 0 1 1 0 1 0 0 1 0 1 15 1 1 0 0 1 1 1 1 0 1 1 0 116 1 1 1 0 1 1 1 0 0 1 0 1 1 17 1 0 0 1 1 1 0 0 1 0 0 1 1 18 1 1 0 1 1 11 1 0 0 0 0 0 19 1 0 0 0 0 1 1 0 0 0 0 0 0

Channel-coded bits b₀, b₁, b₂, b₃, . . . , b_(B-1) may be generatedaccording to Equation 9.

$\begin{matrix}{b_{i} = {\sum\limits_{n = 0}^{A - 1}{\left( {a_{n} \cdot M_{i,n}} \right){mod}\; 2}}} & \left\lbrack {{Equation}\mspace{14mu} 9} \right\rbrack\end{matrix}$

Here, i=0, 1, 2, . . . , B−1.

Table 11 shows an uplink control information (UCI) field for widebandreport (single antenna port, transmit diversity or open loop spatialmultiplexing PDSCH) CQI feedback.

TABLE 11 Field Band Wideband CQI 4

Table 12 shows a UCI field for wideband CQI and PMI feedback. This fieldreports closed loop spatial multiplexing PDSCH transmission.

TABLE 12 Band 2 antenna ports 4 antenna ports Field Rank = 1 Rank = 2Rank = 1 Rank > 1 Wideband CQI 4 4 4 4 Spatial 0 3 0 3 differential CQIPMI(Preceding 2 1 4 4 Matrix Index)

Table 13 shows a UCI field for RI feedback for wideband report.

TABLE 13 Bit widths 4 antenna ports 2 antenna Maximum 2 Maximum 4 Fieldports layers layers RI(Rank 1 1 2 Indication)

FIG. 19 illustrates PRB allocation. As shown in FIG. 19, a PRB may beused for PUCCH transmission in slot n_(s).

A multi-carrier system or a carrier aggregation system means a systemusing aggregation of a plurality of carriers having a bandwidth narrowerthan a target bandwidth for supporting a wideband. When the plurality ofcarriers having a bandwidth narrower than the target bandwidth areaggregated, the bandwidth of the aggregated carriers may be limited tothe bandwidths used in existing systems for backward compatibility withthe existing systems. For example, an LTE system supports bandwidths of1.4 MHz, 3 MHz, 5 MHz, 10 MHz, 15 MHz and 20 MHz and an LTE-A systemevolved from the LTE system can support bandwidths wider than 20 MHzusing bandwidths supported by the LTE system. Alternatively, a newbandwidth may be defined to support carrier aggregation irrespective ofthe bandwidths used in existing systems. The term ‘multi-carrier’ can beused with carrier aggregation and bandwidth aggregation. Carrieraggregation includes both contiguous carrier aggregation andnon-contiguous carrier aggregation.

FIG. 20 illustrates a concept of management of downlink componentcarriers in a BS and FIG. 21 illustrates a concept of management ofuplink component carriers in a UE. For convenience, higher layers aresimply referred to as a MAC layer in the following description.

FIG. 22 illustrates a concept of management of multiple carriers by oneMAC layer in a BS and FIG. 23 illustrates a concept of management ofmultiple carriers by MAC layer in a UE.

Referring to FIGS. 22 and 23, one MAC layer manages and operates one ormore frequency carriers for transmission and reception. In this case,resource management is flexible because frequency carriers managed byone MAC layer need not be contiguous. In FIGS. 22 and 23, one PHY layercorresponds to one component carrier. Here, one PHY layer does notnecessarily mean an independent radio frequency (RF) device. While oneindependent RF device means one PHY layer in general, one RF device isnot limited thereto and may include multiple PHY layers.

FIG. 24 illustrates a concept of management of multiple carriers bymultiple MAC layers in a BS and FIG. 25 illustrates a concept ofmanagement of multiple carriers by multiple MAC layers in a UE. FIG. 26illustrates a concept of management of multiple carriers by multiple MAClayers in a BS and FIG. 27 illustrates a concept of management ofmultiple carriers by one or more MAC layers in a UE.

Distinguished from the structures shown in FIGS. 22 and 23, multiplecarriers may be controlled by multiple MAC layers as shown in FIGS. 24to 27.

Multiple MAC layers may control one-to-one multiple carriers as shown inFIGS. 24 and 25. Referring to FIGS. 26 and 27, MAC layers may controlone-to-one some carriers and one MAC layer may control other carriers.

The above-described system includes one to N carriers which arecontiguous or non-contiguous. This can be applied in uplink anddownlink. A TDD system is constructed such that N carriers for downlinktransmission and uplink transmission are operated and an FDD system isconstructed such that multiple carriers are respectively used for uplinkand downlink. The FDD system may support asymmetrical carrieraggregation in which the number of aggregated carriers and/or a carrierbandwidth in uplink is different from those in downlink.

When the number of aggregated component carriers in uplink equals thatin downlink, it is possible to configure all component carriers suchthat they are compatible with existing systems. However, componentcarriers that do not consider compatibility are not excluded from thepresent invention.

While the following description is made on the assumption that, when aPDCCH is transmitted using downlink component carrier #0, a PDSCHcorresponding to the PDCCH is transmitted through downlink componentcarrier #0, it is apparent that the PDSCH can be transmitted through adifferent downlink component carrier using cross-carrier scheduling. Theterm “component carrier” can be replaced with an equivalent term (e.g.cell).

FIG. 28 illustrates a general carrier aggregation scenario. It isassumed that 2 DL CCs and 2 UL CCs are configured for convenience ofdescription.

Referring to FIG. 28, a UL CC includes one UL primary CC (UL PCC) andone UL secondary CC (UL SCC). The UL PCC can be defined as a UL CCcarrying a PUCCH, UCI or PUCCH/UCI. While a plurality of DL PCCs may bepresent, it is assumed that one

DL PCC is present in the present embodiment for easiness of description.Furthermore, while a plurality of DL SCCs may be present, it is assumedthat one DL SCC is present in the present embodiment for easiness ofdescription. A 2DL:2UL configuration shown in FIG. 28 is exemplary andit is apparent that other CA configurations (e.g. a configuration ofthree or more DL CCs (UL CCs)) can be used. DL-UL linkage can bedetermined from UL linkage through UL EARFCN information of SIB2.

A DL PCC can be defined as a DL CC linked with a UL PCC. Here, linkageincludes both implicit linkage and explicit linkage. In LTE, one DL CCand one UL CC are uniquely paired. For example, a DL CC linked with a ULPCC can be referred to as a DL PCC, according to LTE pairing. This canbe regarded as implicit linkage. Explicit linkage means that a networkconfigures linkage in advance and may be RRC-signaled. In explicitlinkage, a DL CC paired with a UL PCC can be referred to as a DL PCC.The DL PCC can be configured through higher layer signaling. Otherwise,the DL PCC may be a DL CC initially accessed by a UE. DL CCs other thanthe DL PCC can be referred to as DL SCCs. Similarly, UL CCs other thanthe UL PCC can be referred to UL SCCs.

FIG. 29 illustrates a scenario of transmitting UCI in a wirelesscommunication system that supports carrier aggregation. This scenario isbased on the assumption that UCI is ACK/NACK (A/N). However, this isexemplary and UCI can include control information such as channel statusinformation (e.g. CQI, PMI, RI, etc) and scheduling request information(e.g. SR).

FIG. 29 illustrates asymmetrical carrier aggregation in which 5 DL CCsare linked to one UL CC. This asymmetrical carrier aggregation may beset from the viewpoint of UCI transmission. That is, DL CC-UL CC linkagefor the UCI and DL CC-UL CC linkage for data may be different from eachother. When it is assumed that one DL CC can transmit a maximum of twocodewords, at least two UL ACK/NACK bits are needed. In this case, atleast 10 ACK/NACK bits are necessary to transmit ACK/NACK informationfor data, received through 5 DL CCs, using one UL CC. If DTX status isalso supported for each DL CC, at least 12 bits (=5⁵=3125=11.6 bits) areneeded for ACK/NACK transmission. The conventional PUCCH formats 1a/1bcan transmit ACK/NACK information having a maximum of 2 bits, and thusit cannot transmit ACK/NACK information having an increased number ofbits. While it has been described that carrier aggregation increases thequantity of UCI, an increase in the number of antennas, presence of abackhaul subframe in a TDD system and a relay system, etc. may cause anincrease in the quantity of UCI. Similarly to ACK/NACK information, whencontrol information related to a plurality of DL CCs is transmittedthrough one UL CC, the quantity of the control information increases.For example, when CQI/PMI/RI related to a plurality of DL CCs istransmitted, a CQI payload may increase. A DL CC and a UL CC may also berespectively called a DL cell and a UL cell and an anchor DL CC and ananchor UL CC may be respectively called a DL primary cell (PCell) and aUL PCell.

DL-UL pairing may correspond to FDD only. DL-UL pairing may not beadditionally defined for TDD because TDD uses the same frequency. DL-ULlinkage may be determined from UL linkage through UL EARFCN informationof SIB2. For example, DL-UL linkage can be obtained through SIB2decoding in the event of initial access and acquired through RRCsignaling in other cases. Accordingly, only SIB2 linkage is present andother DL-UL pairing may not be explicitly defined. For example, in a5DL:1UL structure shown in FIG. 28, DL CC#0 and UL CC#0 is in a SIB2linkage relationship and other DL CCs may be in the SIB2 linkagerelationship with other UL CCs that are not set to the corresponding UE.

While some embodiments of the present invention are focused onasymmetrical carrier aggregation, they are exemplary and the presentinvention is applicable to various carrier aggregation scenariosincluding symmetrical carrier aggregation.

Embodiment

A scheme for efficiently transmitting an increased quantity of UCI willnow be described. Specifically, a new PUCCH format/signal processingprocedure/resource allocation method for transmitting UCI in increasedquantity are proposed. In the following description, the PUCCH formatproposed by the present invention is referred to as a new PUCCH format,LTE-A PUCCH format, CA PUCCH format or PUCCH format 3 in view of thefact that up to PUCCH format 2 has been defined in LTE. To assist inunderstanding of the present invention, the following description isfocused on a case in which multiple ACK/NACK bits are used as controlinformation in increased quantity. However, the control information isnot limited to multiple ACK/NACK bits in the present invention. PUCCHformat 3 and transmission schemes include the following. The presentinvention can further include PUCCH formats other than the followingexamples.

-   -   Reuse of PUCCH format 2: UCI (e.g. multiple ACK/NACKs) can be        transmitting using PUCCH format 2 or a modified form thereof,        defined in LTE.    -   DFT based PUCCH: Information can be transmitted by DFT precoding        and application of a time domain orthogonal cover (OC) at an        SC-FDMA symbol level. This will be described in detail below        with reference to FIG. 30.    -   SF reduction: A symbol space can be doubled by reducing a time        domain spreading factor from 4 to 2 in LTE PUCCH format 1a/1b.        Information bits may be channel-coded or not. This will be        described later in detail with reference to FIG. 31.    -   Channel selection: When multiple PUCCH resources are provided,        information can be transmitted by combining the number of cases        of selecting a specific PUCCH resource and constellation        modulated to the corresponding PUCCH resource. For example,        assuming that 2 PUCCH resources are present and QPSK modulation        is employed, a total of 8(=2*4) states (=3 bits) can be        transmitted.    -   MSM (Multi-sequence modulation): Information can be transmitted        by modulating different pieces of information for each of        multiple PUCCHs. For example, assuming that 2 PUCCH resources        are present and QPSK modulation is employed, a total of 16        states (=4*4=4 bits) can be transmitted when the information is        not coded.    -   Hybrid approach: A combination of at least two of formats        including the aforementioned formats as well as other formats.        For example, channel selection and SF reduction can be combined.

FIG. 30 illustrates signal transmission using PUCCH format 3.

Referring to FIG. 30, one DL primary component carrier (DL PCC) and oneDL secondary component carrier (DL SCC) are present. The DL PCC may belinked with a UL PCC. It is assumed that each of the DL PCC and the DLSCC includes one DL grant and a PDCCH is transmitted through each CC. Ifeach DL CC transmits 2 codewords (a total of 4 codewords), it ispossible to transmit, through PUCCH format 3 on the UL PCC, 4 bits whena DTX status is not reported and 5 bits when the DTX status is reported.

A description will be given of a DFT-based PUCCH format as an example ofPUCCH format 3 with reference to the attached drawings.

For convenience, in the following description, the UCI/RS symbolstructure of the conventional PUCCH format 1 (normal CP) of LTE is usedas a subframe/slot based UCI/RS symbol structure applied to PUCCH format3 according to an embodiment of the present invention. However, thesubframe/slot based UCI/RS symbol structure is exemplary and the presentinvention is not limited to a specific UCI/RS symbol structure. In thePUCCH format according to the present invention, the number of UCI/RSsymbols, positions of the UCI/RS symbols, etc. may be freely changedaccording to system design. For example, the PUCCH format according toan embodiment of the present invention can be defined using the RSsymbol structures of PUCCH format 2/2a/2b of LTE.

The PUCCH format according to embodiments of the present invention canbe used to transmit UCI of an arbitrary type and in an arbitrary size.For example, PUCCH format 3 can transmit information such as ACK/NACK,CQI, PMI, RS, SR, etc. This information may have a payload of anarbitrary size. For convenience, description of the followingembodiments and drawings are focused on a case in which the PUCCH formataccording to the present invention transmits ACK/NACK information.

FIGS. 31 a to 31 f illustrate structures of PUCCH format 3 and signalprocessing procedures for the same according to an embodiment of thepresent invention. The present embodiment describes a DFT based PUCCHformat. In the present embodiment, an RS can use the structure of LTE.For example, the RS can be obtained by applying a cyclic shift to a basesequence.

FIG. 31 a illustrates a case in which PUCCH format 3 according to thepresent invention is applied to PUCCH format 1 (normal CP). Referring toFIG. 31 a, a channel coding block channel-codes information bits a_0,a_1, . . . , a_M−1 (e.g. multiple ACK/NACK bits) to generate encodedbits (coded bits or coding bits) (or a codeword) b_0, b_1, . . . ,b_N−1. Here, M denotes an information bit size and N denotes an encodedbit size. The information bits include multiple ACK/NACK bits for aplurality of data (or PDSCH) received through a plurality of DL CCs, forexample. The information bits a_0, a_1, . . . , a_M−1 are joint-codedregardless of the type/number/size of UCI that forms the informationbits. For example, when the information bits include multiple ACK/NACKbits for a plurality of DL CCs, channel coding is performed for allinformation bits instead of each DL CC and each ACK/NACK bit to generatea single codeword. Channel coding includes simple repetition, simplexcoding, RM coding, punctured RM coding, Tail-biting convolutional coding(TBCC), low-density parity-check (LDPC) or turbo-coding but is notlimited thereto. The encoded bits can be rate-matched in considerationof a modulation order and resource quantity, which is not shown in thefigure. The rate matching function may be included in the channel codingblock or may be executed through a separate functional block.

A modulator modulates the encoded bits b_0, b_1, . . . , b_N−1 togenerate modulation symbols c_0, c_1, . . . , c_L−1 where L denotes thesize of the modulation symbols. A modulation method is performed bymodifying the size and phase of a transport signal. For example, themodulation method includes n-PSK (Phase Shift Keying) and n-QAM(Quadrature Amplitude Modulation) (n being an integer greater than orequal to 2). Specifically, the modulation method may include BPSK(Binary PSK), QPSK (Quadrature PSK), 8-PSK, QAM, 16-QAM, 64-QAM, etc.

A divider divides the modulation symbols c_0, c_1, . . . , c_L−1 intoslots. The order/pattern/scheme of dividing the modulation symbols intoslots are not particularly limited. For example, the divider cansequentially divide the modulation symbols into the slots (localizedtype). In this case, modulation symbols c_0, c_1, . . . , c_L/2−1 can bedivided into slot 0 and modulation symbols c_L/2, c_L/2+1, . . . , c_L−1can be divided into slot 1, as shown in FIG. 29 a. Furthermore, themodulation symbols may be interleaved (permuted) when divided into theslots. For example, even-numbered modulation symbols can be divided intoslot 0 and odd-numbered modulation symbols can be divided into slot 1.The order of the modulation operation and division operation may bechanged.

A DFT precoder performs DFT precoding (e.g. 12-point DFT) for themodulation symbols divided into each slot in order to generate a singlecarrier waveform. Referring to FIG. 29 a, the modulation symbols c_0,c_1, . . . , c_L/2−1 divided into slot 0 can be DFT-precoded into DFTsymbols d_0, d_1, . . . , d_L/2−1 and the modulation symbols c_L/2,c_L/2+1, . . . , c_L−1 divided into slot 1 can be DFT-precoded into DFTsymbols d_L/2, d_L/2+1, . . . , d_L−1. DFT precoding can be replaced byother corresponding linear operation (e.g. Walsh precoding).

A spreading block spreads a DFT precoded signal at an SC-FDMA symbollevel (time domain). SC-FDMA symbol level time domain spreading isperformed using a spreading code (sequence). The spreading code includesa quasi-orthogonal code and an orthogonal code. The quasi-orthogonalcode includes a pseudo noise (PN) code. However, the quasi-orthogonalcode is not limited thereto. The orthogonal code includes a Walsh codeand a DFT code. However, the orthogonal code is not limited thereto. Inthe following description, the orthogonal code is used as the spreadingcode for ease of description. However, the orthogonal code is exemplaryand can be replaced by the quasi-orthogonal code. A maximum spreadingcode size (or spreading factor SF) is limited by the number of SC-FDMAsymbols used for control information transmission. For example, when 4SC-FDMA symbols are used for control information transmission in oneslot, a (quasi) orthogonal code w0,w1,w2,w3 having a length of 4 can beused for each slot. The SF means a spreading degree of controlinformation and may be related to a UE multiplexing order or an antennamultiplexing order. The SF can be changed to 1, 2, 3, 4, . . . accordingto system requirements and pre-defined between a BS and a UE or signaledto the UE through DCI or RRC signaling. For example, when one of SC-FDMAsymbols for control information is punctured in order to transmit anSRS, a spreading code with a reduced SF (e.g. SF=3 instead of SF=4) canbe applied to control information of a corresponding slot.

The signal generated through the above-mentioned procedure is mapped tosubcarriers in a PRB and then subjected to IFFT to be transformed into atime domain signal. A cyclic prefix is added to the time domain signalto generate SC-FDMA symbols which are then transmitted through an RFunit.

The above-mentioned procedure will now be described in more detail onthe assumption that ACK/NACK bits for 5 DL CCs are transmitted. Wheneach DL CC can transmit 2 PDSCHs, ACK/NACK bits for the DL CC may be 12bits when they include a DTX status. A coding block size (after ratematching) may be 48 bits on the assumption that QPSK and SF=4 timespreading are used. Encoded bits are modulated into 24 QPSK symbols and12 QPSK symbols are divided per slot. In each slot, 12 QPSK symbols areconverted to 12 DFT symbols through 12-point DFT. In each slot, 12 DFTsymbols are spread and mapped to 4 SC-FDMA symbols using a spreadingcode with SF=4 in the time domain. Since 12 bits are transmitted through[2 bits×12 subcarriers×8 SC-FDMA symbols], the coding rate is0.0625(=12/192). In the case of SF=4, a maximum of 4 UEs can bemultiplexed per PRB.

The signal mapped to the PRB in the procedure shown in FIG. 31 a may beobtained through various equivalent signal processing procedures. Signalprocessing procedures equivalent to the signal processing procedure ofFIG. 31 a will now be described with reference to FIGS. 31 b to 31 g.

FIG. 31 b shows a case in which the order of operations of the DFTprecoder and the spreading block of FIG. 31 a is changed. The functionof the spreading block corresponds to operation of multiplying a DFTsymbol sequence output from the DFT precoder by a specific constant atthe SC-FMDA symbol level, and thus the same signal value is mapped toSC-FDMA symbols even though the order of operations of the DFT precoderand the spreading block is changed. Accordingly, the signal processingprocedure for PUCCH format 3 can be performed in the order of channelcoding, modulation, division, spreading and DFT precoding. In this case,the division and spreading may be performed by one functional block. Forexample, modulation symbols can be alternately divided into slots and,simultaneously, spread at the SC-FDMA symbol level. Alternatively, themodulation symbols can be copied such that they correspond to the sizeof a spreading code when divided into the slots, and the copiedmodulation symbols can be multiplied one-to-one by respective elementsof the spreading code. Accordingly, a modulation symbol sequencegenerated for each slot is spread to a plurality of SC-FDMA symbols.Then, a complex symbol stream corresponding to the SC-FDMA symbols isDFT-precoded for each SC-FDMA symbol.

FIG. 31 c shows a case in which the order of operations of the modulatorand the divider of FIG. 31 a is changed. In this case, in the signalprocessing procedure for PUCCH format 3, joint channel coding anddivision are performed at the subframe level, and modulation, DFTprecoding and spreading are sequentially performed at the slot level.

FIG. 31 d shows a case in which the order of operations of the DFTprecoder and the spreading block of FIG. 31 c is changed. As describedabove, since the function of the spreading block corresponds tooperation of multiplying a DFT symbol sequence output from the DFTprecoder by a specific constant at the SC-FMDA symbol level, the samesignal value is mapped to SC-FDMA symbols even though the order ofoperations of the DFT precoder and the spreading block is changed.Accordingly, in the signal processing procedure for PUCCH format 3,joint channel coding and division are performed at the subframe level,and modulation is carried out at the slot level. The modulation symbolsequence generated for each slot is spread to a plurality of SC-FDMAsymbols and DFT-precoded for each SC-FDMA symbol. In this case, themodulation and spreading operations can be performed by one functionalblock. For example, the generated modulation symbols can be directlyspread at the SC-FDMA symbol level during modulation of the encodedbits. Alternatively, during modulation of the encoded bits, thegenerated modulation symbols can be copied such that they correspond tothe size of the spreading code and multiplied one-to-one by respectiveelements of the spreading code.

FIG. 31 e shows a case in which PUCCH format 3 according to the presentembodiment is applied to PUCCH format 2 (normal CP) and FIG. 30 f showsa case in which PUCCH format 3 according to the present embodiment isapplied to PUCCH format 2 (extended CP). While a basic signal processingprocedure is the same as the procedures described with reference toFIGS. 31 a to 31 d, the numbers/positions of UCI SC-FDMA symbols and RSSC-FDMA symbols are different from those of FIG. 31 a since PUCCH format2 of LTE is reused.

Table 14 shows RS SC-FDMA symbol position in PUCCH format 3. It isassumed that the number of SC-FDMA symbols in a slot is 7 (indexes: 0 to6) in case of normal CP and 6 (indexes: 0 to 5) in case of extended CP.

TABLE 14 RS SC-FDMA symbol position Normal CP Extended CP Note PUCCH 2,3, 4 2, 3 Reuse PUCCH format 3 format 1 1, 5 3 Reuse PUCCH format 2

Tables 15 and 16 show exemplary spreading codes according to SF value.Table 15 shows DFT codes with SF=5 and SF=3 and Table 16 shows Walshcodes with SF=4 and SF=2. A DFT code is an orthogonal code representedby w _(m)=[w₀ w₁ . . . w_(k-1)], where w_(k)=exp (j2πkm/SF) where kdenotes a DFT code size or SF value and m is 0, 1, . . . , SF-1. Tables15 and 16 show a case in which m is used as an index for an orthogonalcode.

TABLE 15 Orthogonal code w _(m) = [w₀ w₁ . . . w_(k−1)] Index m SF = 5SF = 3 0 [1 1 1 1 1] [1 1 1] 1 [1 e^(j2π/5) e^(j4π/5) e^(j6π/5)e^(j8π/5)] [1 e^(j2π/3) ^(ej4π/3)] 2 [1 e^(j4π/5) e^(j8π/5) e^(j2π/5)e^(j6π/5)] [1 e^(j4π/3) ^(ej2π/3)] 3 [1 e^(j6π/5) e^(j2π/5) e^(j8π/5)e^(j4π/5)] 4 [1 e^(j8π/5) e^(j6π/5) e^(j4π/5) e^(j2π/5)]

TABLE 16 Orthogonal code Index m SF = 4 SF = 2 0 [+1 +1 +1 +1] [+1 +1] 1[+1 −1 +1 −1] [+1 −1] 2 [+1 +1 −1 −1] 3 [+1 −1 −1 +1]

Code index m may be designated in advance or signaled from the BS. Forexample, the code index m can be implicitly linked with a CCE index(e.g. the lowest CCE index) constituting a PDCCH. The code index m maybe explicitly designated through a PDCCH or RRC signaling. Furthermore,the code index m may be derived from a value designated through thePDCCH or RRC signaling. The code index m may be independently given foreach subframe, each slot, and multiple SC-FDMA symbols. Preferably, thecode index m can be changed for each subframe, each slot and multipleSC-FDMA symbols. That is, the code index m can be hopped at apredetermined interval.

Cell-specific scrambling using a scrambling code (e.g. a PN code such asa Gold code) corresponding to a physical cell ID (PCI) or UE-specificscrambling using a scrambling code corresponding to a UE ID (e.g. RNTI)can be additionally applied for inter-cell interference randomization,which is not shown in the figure. Scrambling may be performed for theentire information, performed in SC-FDMA symbols, carried out betweenSC-FDMA symbols, or carried out for both the entire information andSC-FDMA symbols. Scrambling the entire information can be achieved byperforming scrambling on the information bits, encoded bits andmodulation symbols prior to division. Intra-SC-FMDA symbol scramblingmay be implemented by performing scrambling on the modulation symbols orDFT symbols after division. Inter-SC-FDMA symbol scrambling may beachieved by carrying out scrambling on the SC-FDMA symbols in the timedomain after spreading.

UE multiplexing can be achieved by applying CDM to a signal before beingsubjected to the DFT precoder. For example, the signal before beingsubjected to the DFT precoder is a time domain signal, and thus CDM canbe implemented through circular shift (or cyclic shift) or Walsh (orDFT) spreading. CDM can be performed for one of the information bits,encoded bits and modulation symbols. Specifically, a case ofmultiplexing 2 UEs to one SC-FDMA symbol using a Walsh code with SF=2 isexemplified. When QPSK is performed on 12 encoded bits, a complex signalof a₀ a₁ a₂ a₃ a₄ a₅ is generated. Control information of each UE isspread using Walsh code [+1 +1] [+1−1] as follows.

-   -   UE#0: [+1 +1] is applied. a₀ a₁ a₂ a₃ a₄ a₅ a₀ a₁ a₂ a₃ a₄ a₅        are transmitted.    -   UE#1: [+1 −1] is applied. a₀ a₁ a₂ a₃ a₄ a₅ −a₀ −a₁ −a₂ −a₃ −a₄        −a₅ are transmitted.

In this case, interleaving may be additionally performed. Theinterleaving may be applied before or after spreading. Both thespreading and interleaving are applied as follows.

-   -   UE#0: [+1 +1] is applied. a₀ a₀ a₁ a₁ a₂ a₂ a₃ a₃ a₄ a₄ a₅ a₅        are transmitted.    -   UE#1: [+1 −1] is applied. a₀, −a₀, a₁, −a₁, a₂, −a₂, a₃, −a₃,        a₄, −a₄, a₅, −a₅ are transmitted.

A signal generated from spreading and/or interleaving in a stage priorto the DFT precoder is subjected to DFT precoding (and additionallysubjected to SC-FDMA symbol level time spreading as necessary) andmapped to subcarriers of the corresponding SC-FDMA symbols.

FIG. 32 illustrates another structure of PUCCH format 3 according to anembodiment of the present invention. This structure shows a PUCCH formatto which SF reduction is applied. In this structure, an RS uses theconventional RS structure of LTE. For example, the RS can be obtained byapplying a cyclic shift to a base sequence.

Referring to FIG. 32, information bits (e.g. ACK/NACK) are convertedinto modulation symbols (symbols 0 and 1) through modulation (e.g. QPSK,8PSK, 16QAM, 64QAM or the like). The modulation symbols are multipliedby a base sequence r0, and a cyclic shift and an orthogonal code (OC)([w0 w1];[w2 w3]) with SF=2 are sequentially applied to the modulationsymbols. Then, the modulation symbols to which the cyclic shift and OChave been applied are subjected to IFFT and then are mapped to SC-FDMAsymbols. Here, r0 includes a base sequence having a length of 12. The OCincludes a Walsh cover or a DFT code defined in LTE. Orthogonal codes[w0 w1] and [w2 w3] may be independently provided or may have the samevalue according to implementation scheme.

LTE PUCCH format 1a/1b can transmit only one modulation symbol in oneslot because it uses SF=4. Furthermore, since the same information isrepeated on a slot basis, LTE PUCCH format 1a/1b can transmit only onemodulation symbol at a subframe level. Accordingly, LTE PUCCH formatscan transmit ACK/NACK information having a maximum of 2 bits in case ofQPSK. However, the PUCCH format illustrated in FIG. 31 can transmit twomodulation symbols per slot due to SF reduction. Furthermore, if slotsare configured such that they transmit different pieces of information,a maximum of 4 modulation symbols can be transmitted at the subframelevel. Therefore, the illustrated PUCCH format can transmit UCI (e.g.ACK/NACK) having a maximum of 8 bits in case of QPSK.

Embodiment 1 Resource Allocation for PUCCH Format 3

A resource for PUCCH format 3 may be explicitly allocated to a UE. Forconvenience, the resource for PUCCH format 3 is referred to as a PUCCHresource in the following description unless otherwise especiallystated. For example, when the structure shown in FIG. 3 is used as PUCCHformat 3, the PUCCH resource includes a code index for spreading and aPRB index. In addition, when the structure shown in FIG. 3 is used asPUCCH format 3, the PUCCH resource includes a cyclic shift value, anorthogonal code index and a PRB index. The cyclic shift value, codeindex and PRB index may be individually provided or inferred from onelogical representative value. For example, in case of LTE, the resourcefor PUCCH format 1 is inferred from a logical representative valuen_(PUCCH) ⁽¹⁾. Similarly, the resource for PUCCH format 3 may beinferred from a logical representative value n_(PUCCH) ⁽³⁾.

As an example of explicit resource allocation, the PUCCH resource may beallocated through higher layer signaling (e.g. RRC signaling) and may beshared by multiple UEs. If the PUCCH resource is exclusively allocatedto all UEs, overhead may be remarkably increased, although resourcecollision is not generated. Resource sharing by multiple UEs enablesefficient resource management. For example, assuming that UE#0 and UE#1share PUCCH resource #A, when a DL packet for UE#0 and a DL packet forUE#1 are respectively transmitted on different subframes, thecorresponding ACK/NACK feedbacks (in subframe n+4) do no collide andthus the shared PUCCH resource #A can be efficiently used. However, ifUE#0 and UE#1 are simultaneously scheduled in subframe #n, resourcecollision occurs because the two UEs transmit ACK/NACK using PUCCHresource #A.

To solve this problem, the present invention proposes a scheme oftransmitting resource indication information (e.g. an offset, an index)for a PUCCH through a PDCCH (e.g. DL grant PDCCH). According to thisscheme, it is possible to avoid resource collision by indicating thePUCCH resource using the resource indication information.

FIG. 33 illustrates a PUCCH transmission method according to anembodiment of the present invention.

Referring to FIG. 33, a BS transmits PUCCH resource configurationinformation to a UE through higher layer signaling (e.g. RRC signaling)(S3310). The PUCCH resource configuration information indicates one ormore PUCCH resources to the UE, and the one or more PUCCH resourcesindicated by the PUCCH resource configuration information are occupiedfor the UE. Then, the BS transmits a PDCCH for downlink scheduling tothe UE (S3320). In the present embodiment, the PDCCH includes resourceindication information (e.g. offset, index) relating to the PUCCHresource. The resource indication information may be transmitted using afield additionally defined in DCI or reusing a previously defined field.Furthermore, considering a case in which the UE misses the PDCCH, aplurality of PDCCHs may have the same resource indication information.For example, offset values transmitted over all PDCCHs can have the samevalue on all DL CCs. Then, the BS transmits a PDSCH indicated by thePDCCH to the UE (S3330). Upon receipt of the PDSCH, the UE transmits anACK/NACK signal for the PDSCH to the BS through a PUCCH resource(S3340). Here, the PUCCH resource used to transmit the ACK/NACK signalis obtained using the PUCCH resource configuration information of stepS3310 and the resource indication information of step S3320.

The above-mentioned PUCCH transmission method is described in moredetail. For convenience of description, it is assumed that UE#0 and UE#1share PUCCH resource #A and a BS schedules UE#0 and UE#1 in subframe #nas follows.

-   -   UE#0: Transmits PDCCH#0 on DL CC#0, transmits PDCCH#1 on DL CC#1        and transmits offset=0 in each PDCCH.    -   UE#1: Transmits PDCCH#0 on DL CC#0, transmits PDCCH#1 on DL CC#1        and transmits offset=2 in each PDCCH.

In this case, UE#0 transmits ACK/NACK using PUCCH resource #(A+0) andUE#1 transmits ACK/NACK using PUCCH resource #(A+2).

To allow UE#1 to use PUCCH resource #(A+2), it is necessary topre-assign at least both PUCCH resource #A and PUCCH resource #(A+2) toUE#1. That is, it is possible to efficiently prevent PUCCH resourcecollision by pre-allocating a plurality of PUCCH resources (or a PUCCHresource set) to each UE (group) and indicating a PUCCH resource to beused for actual transmission using the resource indication informationaccording to circumstance. The PUCCH resource set may be UE-specificallyor UE group-specifically provided.

In this case, the BS can previously assign a plurality of PUCCHresources, which can be used by a UE, to the UE through higher layersignaling and designate a PUCCH resource to be used by the UE in acorresponding instance (e.g. subframe) through a DL grant. For example,when the BS explicitly configures (e.g. RRC signaling) PUCCH resources#0, #1, #2 and #3 for UE#0 and indicates PUCCH #2 through a DL grant fora DL SCC, UE#0 feeds back ACK/NACK through PUCCH resource #2. PUCCHresources #0, #1, #2 and #3 may be contiguously or non-contiguouslyconfigured in a PUCCH resource domain.

An offset value for indicating a PUCCH resource may be an absoluteoffset value or a relative offset value. When the resource indicationinformation is a relative offset value, the offset value may correspondto the order of a plurality of PUCCH resources configured by a higherlayer.

A description will be given of a scheme of transmitting the resourceindication information using a conventional DCI field. A 2-bit transmitpower control (TPC) field for UL PUCCH power control is defined in DLgrant (DCI formats 1, 1A, 1B, 1D, 2, 2A and 2B) of LTE. When carrieraggregation is supported, a UE can perform UL PUCCH power control usingonly a TPC field value transmitted on one DL CC (e.g. DL PCC) because aPUCCH is transmitted on one UL PCC only. Accordingly, a TPC field valuetransmitted on a DL SCC can be used to transmit the resource indicationinformation (e.g. offset, index) for indicating a PUCCH resource.Preferably, resource indication information transmitted on DL SCCs canbe identical in consideration of a PDCCH missing case. That is, TPCfields transmitted on DL SCCs can be set to the same value.

More specifically, it is assumed that UE#0 and UE#1 share PUCCH resource#A and a BS schedules UE#0 and UE#1 in subframe #n as follows.

-   -   UE#0: PDCCH#0 is transmitted on DL CC#0, a TPC value in PDCCH#0        DCI is used for UL PCC PUCCH power control, PDCCH#S0 is        transmitted on DL SCC#0, PDCCH#S1 is transmitted on DL SCC#S1,        and TPC values in PDCCH#S0 and PDCCH#S1 DCI indicate 0.    -   UE#1: PDCCH#0 is transmitted on DL CC#0, the TPC value in        PDCCH#0 DCI is used for UL PCC PUCCH power control, PDCCH#S0 is        transmitted on DL SCC#0, PDCCH#S1 is transmitted on DL SCC#S1,        and TPC values in PDCCH#S0 and PDCCH#S1 DCI indicate 2.

In this case, UE#0 transmits ACK/NACK using PUCCH resource #(A+0) andUE#1 transmits ACK/NACK using PUCCH resource #(A+2). In the presentembodiment, even when UE#0 or UE#1 misses one of the DL SCCs, it ispossible to correctly infer a PUCCH resource using a PDCCH of another DLSCC.

In case of a 2-bit TPC field, TPC field values of a DL SCC PDCCH canrepresent four states. The states can be one-to-one linked to aplurality of (e.g. 4) PUCCH resources. For example, TPC field values 0to 3 of the DL SCC PDCCH can be used as offset values (or index values,sequence values) that indicate PUCCH resources. An offset value forindicating a PUCCH resource can be an absolute offset value or arelative offset value. When the TPC field indicates a relative offsetvalue, the TPC values 0 to 3 can respectively indicate first to fourthPUCCH resources. For example, when PUCCH resources #0, #1, #2 and #3 areexplicitly set (e.g. RRC signaled) and a TPC field value of a DL grandfor a DL SCC indicates PUCCH resource #2, UE#0 can feed back ACK/NACKusing PUCCH resource #2. PUCCH resources #0, #1, #2 and #3 may becontiguously or non-contiguously configured in the PUCCH resourcedomain.

Table 17 shows the mapping relationship between TPC field values andPUCCH resources when the PUCCH resources are indicated using a 2-bit TPCfield of a DL SCC.

TABLE 17 TPC value PUCCH resource (e.g., n_(PUCCH) ⁽³⁾) ‘00’ The 1stPUCCH resource value configured by the higher layers ‘01’ The 2nd PUCCHresource value configured by the higher layers ‘10’ The 3rd PUCCHresource value configured by the higher layers ‘11’ The 4th PUCCHresource value configured by the higher layers

The method for solving resource collision by explicitly allocating (e.g.RRC signaling) to a UE a PUCCH resource that can be shared between UEshas been described.

This method can be equally applied to a method of implicitly linking aPUCCH resource to a CCE index of PDCCH. For example, a resource indexn_(PUCCH) ⁽³⁾ for PUCCH format 3 can be obtained according to Equation10.

n _(PUCCH) ^((3′)) =n _(CCE) +N _(PUCCH) ⁽¹⁾ +N _(PUCCH) ⁽³⁾+RI  [Equation 10]

Here, n_(CCE) denotes a specific CCE index (e.g. the lowest CCE index)used for PDCCH transmission. N_(PUCCH) ⁽¹⁾ is a value signaled by ahigher layer and relates to PUCCH format 1. And N_(PUCCH) ⁽³⁾ is a valuesignaled by a higher layer and may be an offset for indicating a newresource region for PUCCH format 3. N_(PUCCH) ⁽¹⁾ and N_(PUCCH) ⁽³⁾ maybe signaled as one value. RI denotes a value indicated by the resourceindication information, for example, an offset value.

Alternatively, a specific state of the resource indication informationmay be used as an indicator for PUSCH piggyback. For example, when theresource indication information is transmitted using a 2-bit TPC field,[0 0], [0 1] and [1 0] can be used as resource indication information(e.g. offset values) for PUCCHs and [1 1] can be used as a PUSCHpiggyback indicator. The PUSCH piggyback indicator can be used todynamically perform UCI piggyback in a UE permitted to transmitPUCCH+PUSCH. However, usage of the PUSCH piggyback indicator is notlimited thereto.

Embodiment 2 Resource Allocation for LTE Based PUCCH Format

In carrier aggregation, an LTE UE has occupied a PUCCH resource using anLTE PUCCH format and rule (e.g. CCE based resource allocation).Accordingly, it is possible to transmit a PUCCH on a UL PCC using theLTE PUCCH format and rule when the number of allocated PDCCHs is smallerthan M. Here, the LTE PUCCH format includes LTE PUCCH format 1a/1b, andACK/NACK bundling defined for TDD or LTE PUCCH format 1b based channelselection (in other words, ACK/NACK multiplexing) defined for TDD can beused. A case in which M=1 is explained for convenience of description.

When a PDCCH is scheduled through a DL PCC, the LTE UE can transmit aPUCCH on a UL PCC using the LTE PUCCH format and rule. Since the LTE UEis already using PUCCH resources according to dynamic resourceallocation, the LTE UE can efficiently operate the PUCCH resourceswithout additional overhead when the number of scheduled PDCCHs is lessthan or equal to M (e.g. M=1).

However, when the PDCCH is scheduled to one of DL SCCs, resourcecollision may occur. It is assumed that DL PCC#0 is linked with UL PCC#0for convenience of description. For example, if a PDCCH is not scheduledto DL PCC#0 and a PDCCH is scheduled to DL SCC#0 only, the LTE UEtransmits ACK/NACK information using a PUCCH resource n_B correspondingto the lowest CCE index of the PDCCH transmitted on DL SCC#0 and the LTEPUCCH format. However, when a PUCCH resource corresponding to the lowestCCE index in DL PCC#0, which is assigned to another LTE UE, is n_B,resource collision occurs between the two UEs. To solve this problem, itis necessary to schedule PDCCHs for DL CCs such that the lowest CCEindexes of the PDCCHs do not overlap, which results in schedulingrestriction.

The aforementioned resource collision can be avoided by definingresource indication information (e.g. an offset value) for a PDCCHtransmitted on a DL SCC. For example, it is possible to solve theresource collision problem using a TPC field value as an offset valuewhen the TPC field described in the above embodiment is used.

Alternatively, a specific state of the resource indication informationmay be used as an indicator for PUSCH piggyback. For example, when theresource indication information is transmitted using a 2-bit TPC field,[0 0], [0 1] and [1 0] can be used as resource indication information(e.g. offset values) for PUCCHs and [1 1] can be used as a PUSCHpiggyback indicator. The PUSCH piggyback indicator can be used todynamically perform UCI piggyback in a UE permitted to transmitPUCCH+PUSCH. However, usage of the PUSCH piggyback indicator is notlimited thereto.

Embodiment 3 Resource Allocation for PUCCH Format 3 and LTE PUCCH Format

Resource allocation for PUCCH format 3 and resource allocation for theLTE PUCCH format may be used in connection with each other. In thiscase, the resource indication information (e.g. an offset value or TPCfield) can be used as information for PUCCH format 3 when UCI istransmitted using PUCCH format 3 and be used as information for the LTEPUCCH format when the UCI is transmitted using the LTE PUCCH format.

Embodiment 4 Dynamic LTE Fallback Based on PDCCH on DL SCC

A specific bit in a PDCCH transmitted from a DL SCC can be used as anindicator to operate in an LTE PUCCH format based bundling mode. One ofstates of the resource indication information can indicate operating inthe LTE bundling mode. The resource indication information can betransmitted using a TPC field of a DL SCC PDCCH. Here, bundling means anoperation of feeding back a representative value to a BS through alogical AND operation (or logical OR operation) of fed back ACK/NACKinformation. That is, when the state of the resource indicationinformation is enabled to a bundling mode, a UE can bundle multipleACK/NACK signals to be transmitted using PUCCH format 3 into 1 bit(PUCCH format 1a, full ACK/NACK bundling) or 2 bits (PUCCH format 1b,bundling for each codeword). Here, one of the following resourceallocation rules can be applied.

-   -   A PUCCH resource can be allocated on the basis of the lowest CCE        index of a PDCCH transmitted on a DL PCC.    -   A PUCCH resource can be allocated on the basis of the lowest CCE        index of the first PDCCH in the first (or last) DL CC indexes        (logical or physical). The order of PDCCHs can be determined        based on the sizes of the lowest CCE indexes.    -   A PUCCH resource can be allocated on the basis of the lowest CCE        index of the last PDCCH in the first (or last) DL CC indexes        (logical or physical). The order of PDCCHs can be based on the        sizes of the lowest CCE indexes of the PDCCHs.

Equation 11 represents an example of allocating a PUCCH resource on thebasis of a lowest CCE index in LTE.

n _(PUCCH) =n _(CCE) +N _(PUCCH)  [Equation 11]

Here, n_(PUCCH) denotes a PUCCH resource index, n_(CCE) denotes thelowest CCE index of a PDCCH determined according to the above-mentionedrule, and N_(PUCCH) represents a value signaled by a higher layer.

FIG. 34 is a block diagram showing configurations of a BS and a UE.

Referring to FIG. 34, a wireless communication system includes a BS 110and a UE 120. The BS includes a processor 112, a memory 114, an RF unit116. The processor 112 may be configured to implement the proceduresand/or methods proposed by the present invention. The memory 114 isconnected to the processor 112 and stores information related tooperations of the processor 112. The RF unit 116 is connected to theprocessor 112, transmits and/or receives an RF signal. The UE 120includes a processor 122, a memory 124, and an RF unit 126. Theprocessor 112 may be configured to implement the procedures and/ormethods proposed by the present invention. The memory 124 is connectedto the processor 122 and stores information related to operations of theprocessor 122. The RF unit 126 is connected to the processor 122,transmits and/or receives an RF signal. The BS 110 and/or UE 120 mayinclude a single antenna or multiple antennas.

The embodiments of the present invention described hereinbelow arecombinations of elements and features of the present invention. Theelements or features may be considered selective unless otherwisementioned. Each element or feature may be practiced without beingcombined with other elements or features. Further, an embodiment of thepresent invention may be constructed by combining parts of the elementsand/or features. Operation orders described in embodiments of thepresent invention may be rearranged. Some constructions of any oneembodiment may be included in another embodiment and may be replacedwith corresponding constructions of another embodiment. It will beobvious to those skilled in the art that claims that are not explicitlycited in each other in the appended claims may be presented incombination as an embodiment of the present invention or included as anew claim by a subsequent amendment after the application is filed.

In the embodiments of the present invention, a description is madecentering on a data transmission and reception relationship among a BS,a relay, and an MS. In some cases, a specific operation described asperformed by the BS may be performed by an upper node of the BS. Namely,it is apparent that, in a network comprised of a plurality of networknodes including a BS, various operations performed for communicationwith an MS may be performed by the BS, or network nodes other than theBS. The term ‘BS’ may be replaced with the term ‘fixed station’, ‘NodeB’, ‘enhanced Node B (eNode B or eNB)’, ‘access point’, etc. The term‘UE’ may be replaced with the term ‘Mobile Station (MS)’, ‘MobileSubscriber Station (MSS)’, ‘mobile terminal’, etc.

The embodiments of the present invention may be achieved by variousmeans, for example, hardware, firmware, software, or a combinationthereof. In a hardware configuration, the methods according to theembodiments of the present invention may be achieved by one or moreApplication Specific Integrated Circuits (ASICs), Digital SignalProcessors (DSPs), Digital Signal Processing Devices (DSPDs),Programmable Logic Devices (PLDs), Field Programmable Gate Arrays(FPGAs), processors, controllers, microcontrollers, microprocessors,etc.

In a firmware or software configuration, the embodiments of the presentinvention may be implemented in the form of a module, a procedure, afunction, etc. For example, software code may be stored in a memory unitand executed by a processor. The memory unit is located at the interioror exterior of the processor and may transmit and receive data to andfrom the processor via various known means.

Those skilled in the art will appreciate that the present invention maybe carried out in other specific ways than those set forth hereinwithout departing from the spirit and essential characteristics of thepresent invention. The above embodiments are therefore to be construedin all aspects as illustrative and not restrictive. The scope of theinvention should be determined by the appended claims and their legalequivalents, not by the above description, and all changes coming withinthe meaning and equivalency range of the appended claims are intended tobe embraced therein.

INDUSTRIAL APPLICABILITY

The present invention can be used for a UE, a BS or other devices in awireless communication system. Specifically, the present invention isapplicable to a method for transmitting uplink control information andan apparatus therefor.

1. A method for, at a user equipment (UE), transmittingacknowledgement/negative ACK (ACK/NACK) in a wireless communicationsystem in which carrier aggregation is configured, the methodcomprising: receiving information on a plurality of physical uplinkcontrol channel (PUCCH) resources through higher layer signaling;receiving a transmit power control (TPC) field through a physicaldownlink control channel (PDCCH) on a secondary carrier; receiving dataindicated by the PDCCH; and transmitting ACK/NACK for the data, whereinthe ACK/NACK is transmitted using a PUCCH resource which is indicated bya value of the TPC field, from among the plurality of PUCCH resources.2. The method of claim 1, wherein the TPC field is composed of 2 bitsand the value of the TPC field indicates one of 4 PUCCH resourcesconfigured by a higher layer.
 3. The method of claim 1, wherein thevalue of the TPC field is set to the same value in a plurality of PDCCHsreceived through a plurality of secondary carriers.
 4. The method ofclaim 3, wherein the ACK/NACK includes multiple ACK/NACKs for aplurality of data, and the multiple ACK/NACKs are transmitted through asingle PUCCH resource.
 5. The method of claim 1, wherein the PUCCHresource includes at least one of a physical resource block index and anorthogonal code index.
 6. The method of claim 1, wherein thetransmitting ACK/NACK comprises: spreading ACK/NACK informationcorresponding to one single carrier frequency division multiple access(SC-FDMA) symbol such that the spread ACK/NACK information correspondsto a plurality of SC-FDMA symbols; and discrete Fourier transform(DFT)-precoding the spread ACK/NACK information on an SC-FDMA symbolbasis.
 7. A UE configured to transmit ACK/NACK in a wirelesscommunication system in which carrier aggregation is configured, the UEcomprising: a radio frequency (RF) unit; and a processor, wherein theprocessor is configured to receive information on a plurality of PUCCHresources through higher layer signaling, to receive a TPC field on asecondary carrier through a PDCCH, to receive data indicated by thePDCCH and to transmit ACK/NACK for the data, wherein the ACK/NACK istransmitted using a PUCCH resource which is indicated by a value of theTPC field, from among the plurality of PUCCH resources.
 8. The UE ofclaim 7, wherein the TPC field is composed of 2 bits and the value ofthe TPC field indicates one of 4 PUCCH resources configured by a higherlayer.
 9. The UE of claim 7, wherein the value of the TPC field is setto the same value in a plurality of PDCCHs received through a pluralityof secondary carriers.
 10. The UE of claim 9, wherein the ACK/NACKincludes multiple ACK/NACKs for a plurality of data, wherein themultiple ACK/NACKs are transmitted through a single PUCCH resource. 11.The UE of claim 7, wherein the PUCCH resource includes at least one of aphysical resource block index and an orthogonal code index.
 12. The UEof claim 7, wherein, to transmit the ACK/NACK, the processor isconfigured to spread ACK/NACK information corresponding to one SC-FDMAsymbol such that the spread ACK/NACK information corresponds to aplurality of SC-FDMA symbols and to discrete Fourier transform(DFT)-precode the spread ACK/NACK information on an SC-FDMA symbolbasis.